Currently, the increase in the functionality of various electronic devices is driving the demand for smaller and smaller devices that are easier and more convenient for users to carry and use. This causes many electrical/electronic components within the device to be located closer together. This increases the possibility that the various electronic components in the device will suffer from electromagnetic interference (EMI) or radio frequency interference (RFI) either from RF components such as the antenna, microphone components, RF power amplifiers, etc and subsystems in the device and/or from external sources. The high speed electrical transmission in these devices can produce electromagnetic emissions, which may leak from the connection between the plug connector and its mating connector. These emissions can cause problems in high speed signal transmissions in that they can negatively influence wireless communication between two devices.
Generally, Universal Serial Bus (USB) is a serial bus standard to the PC architecture with a focus on computer interface, consumer and productivity applications. The existing Universal Serial Bus (USB) interconnects have the attributes of plug-and-play and ease of use, from the end user's point of view. Now, as technology innovation marches forward, new kinds of devices, media formats and large inexpensive storage products are converging. They require significantly more bus bandwidth to maintain the interactive experience that users have come to expect. In addition, user applications demand a higher performance between the PC and sophisticated peripherals. The transmission rate of USB 2.0 is insufficient. Consequently, faster serial bus interfaces, such as USB 3.0, have been developed to address the need by adding a higher transmission rate to match usage patterns and devices.
Please refer to FIG. 1 and FIG. 2. FIG. 1 illustrates a perspective view of a conventional electrical receptacle connector, and FIG. 2 is a schematic view of EMI analysis of the conventional electrical receptacle connector. As shown, in the conventional electrical receptacle connector, the base portion and the terminals are received in the metallic shell A1. Therefore, the metallic shell enables the grounding of the conventional electrical receptacle connector and prevents signal interference when transmission. However, the rear cover plate A11 of the metallic shell A1 is devoid of pins. That is, a bottom edge A12 of the rear cover plate A11 is not provided with pins for soldering a circuit board with the metallic shell A1. Here, FIG. 2 is a schematic view of EMI simulation analysis for the conventional electrical receptacle connector mated with a plug electrical connector. It can be clearly seen that, the length of the rear cover plate A11 of the metallic shell A1 is so short, that the gap of between the bottom edge A12 of the rear cover plate A11 and terminal pins or the circuit board is greater than 1.0 mm. From the test results on the distribution of electromagnetic emission leakage, it can be known that a significant magnitude of electromagnetic emissions would leak from the gap, resulting in EMI and RFI problems during signal transmission. Moreover, regarding the rear cover plate A11 be devoid of pins, the securing force between the electrical receptacle connector and the circuit board would be insufficient. Therefore, aforementioned problems of the conventional connector are to be solved.